Our laboratory has recently identified a spontaneous mouse mutant with an ocular phenotype that we will refer to as Big Eyes (BE). Histological analysis of the BE mice indicated an enlarged anterior chamber that correlated with the appearance of an epithelialization of the corneal endothelium and proliferation of these epithelial cells into the iridocorneal angle. It is our hypothesis that blockage of the iridocorneal angle in BE mice produces an increase in intraocular pressure and that this mouse is a model for human diseases such as posterior polymorphous dystrophy (PPD) or iridocorneal endothelial syndrome (ICE) and associated conditions including glaucoma. The preliminary genetics of the BE phenotype suggest a single gene displaying autosomal dominance and numerous genetic modifiers within the mouse genome. The objectives of this proposal are to characterize the clinical and pathological features of the BE phenotype and to identify its underlying genetic causes using a gene mapping approach. [unreadable] [unreadable]